As shown in PR41279, some basic blocks (such as catchswitch) cannot be
instrumented. This patch filters out these BBs in PGO instrumentation.
It also sets the profile count to the fail-to-instrument edge, so that we
can propagate the counts in the CFG.
Differential Revision: https://reviews.llvm.org/D62700
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362995 91177308-0d34-0410-b5e6-96231b3b80d8